JP2003043380A - Optical path conversion method and light switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple optical path conversion method and an optical switch which operate stably. SOLUTION: A fluid medium and switching materials 8 (8a, 8b), which have a refractive index different from that of the fluidic medium and are moved by an electric field, are arranged in between electrodes 411, 421, and 422 arranged facing each other are changed by moving the switching materials 8 (8a, 8b). The electric fields between the electrodes 411 and 421 and 422 and the optical path of the light made incident on the optical switch points 3a and 3b is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an optical path conversion method and an optical switch for changing the optical path of light incident on an optical switch point, and more particularly to WDM (Wave Division Multiplexing) and DW of an optical fiber.
The present invention relates to an optical path changing method and an optical switch that can be suitably used in a DM (Dense Wave Division Multiplexing) communication system and the like.

[0002]

2. Description of the Related Art In recent years, the amount of data transmitted using optical fibers has been increasing year by year. Especially, in the backbone part, optical signals of different wavelengths are superposed on one optical fiber and different wavelengths are transmitted as necessary. WDM (Wave Division Multiplexing) and DW, which are used by dividing into signals for each light
DM (Dense Wave Division Multiplexing) communication systems have been widely used.

Conventionally, a one-to-two optical fiber on the incident side and a large number of optical fibers on the light receiving side are mechanically moved in a direction orthogonal to the optical axis thereof, and are selectively switched to be butted and optically coupled. was there.

However, in the WDM and DWDM communication systems, it is necessary to freely connect and couple the optical signals sent from a large number of optical fibers to the desired optical fiber of the other party. Therefore, a highly efficient multi-matrix is provided.・ Switching is required. That is, Optical Cross Connects (OXCs) and Optical Add / Drop Multiplexing (OADM)
Switching used in.

In the ring type, which has been the mainstream in the past, the line for backup is duplicated, but this is 50%.
Only using the ability. Therefore, if the optical switch is used to form the mesh type, the optical path can be switched at high speed, and it becomes unnecessary to invest extra equipment and have extra capacity.

[0006] In addition, in order to efficiently use the Metro Network from the conventional Long Haul capacity enhancement, and also to improve the investment efficiency for capacity enhancement, the multi-matrix switching is an important position. Is starting to get worse.

In general, as a conventional technique relating to an optical switch, for example, an optical switch using a galvano mirror described in JP-A-7-261101, JP-A-4-011.
229, JP-A-63-225234, JP-A-63-
There is a solid-state optical element (an optical switch using an electro-optical material or a magneto-optical material) described in Japanese Patent No. 147146 or the like by an electric field / magnetic field.

Further, Japanese Patent Laid-Open No. 2000-162520 describes an optical switch in which a light reflecting mirror having a magnetic element supported by a support is movable by an electromagnetic magnet.

In addition to the above, Japanese Patent Laid-Open No. 2000-33004
No. 1 describes a switch using an electrostatic actuator in which an optical mirror section is elastically supported. Such a switch using an electrostatic actuator in which an optical mirror section is elastically supported is a MEMS (Micro Electrical Machine
ine Systems).

On the other hand, regarding the multi-matrix switching as described above, Japanese Patent Laid-Open No. 2000-25870.
No. 5, for example, describes an optical switch using an N × M matrix movable mirror.
No. 12 describes an optical multi-matrix switch that utilizes light reflection by foaming in a liquid using a thermal inkjet technique.

[0011]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
The optical multi-matrix switch described in No. 000-321512 has (1) defective switching operation due to instability of bubbles (2) correction of heat storage required / heater failure (3) inconvenience in high density switching (4) mechanical It has a drawback that durability is lowered due to fatigue of the movable part.

In addition, the optical multi-matrix switch using a thermal ink jet uses bubbles generated by heat in the ink, so that the ejected ink droplets,
Heat is dissipated to the outside of the inkjet head, but by cooling the heat generated from the inkjet head substrate,
It is necessary to always maintain a good condition.

However, even if the heat of heat generated from the substrate of the ink jet head is cooled, it is necessary to further correct the stored heat in order to maintain a constant state.

In other words, an optical multi-system utilizing the light reflection by foaming in the liquid using the thermal ink jet technology.
In the matrix switch, in order to always keep the two-dimensional heat generating substrate in the ink jet head thermally constant, it is necessary to always use the matrix switch while keeping the constant state. However, in order to keep the two-dimensional heat generating substrate thermally constant all the time, it is more difficult to cool and control the linear (one-dimensional) heat generating substrate. Therefore, there are many problems in stable operation.

The above-mentioned MEMS (Micro Elect)
rical Machine Systems) method has many variations of micro mirrors made in each, as seen in projection type displays and scanners using DMD (Digital Miller Device) method in this applied technology area, and there are many variations in operation. There is a problem in stability, and in order to solve this problem, there are many problems at the time of manufacturing, and there is a problem in productivity. Furthermore, MEM
In the method according to S, the supporting portion that supports the metal micromirror portion is repeatedly bent by mechanical movement, and metal fatigue is likely to occur, for example, there is a tendency that reliability for a long period of several decades is lacking. This problem represents an important drawback of switching used in infrastructure.

Further, although there is an optical switch utilizing a liquid crystal or hologram technique, it has a drawback that although the switching speed is relatively high, a large proportion of leaked light is transmitted when reflecting light.

Therefore, a main object of the present invention is to provide an optical path changing method and an optical switch which can perform a simple and stable operation.

Another object of the present invention is to provide an optical path conversion method and an optical switch which can achieve switching with extremely small energy and can change the optical path.

Another object of the present invention is to provide an optical switch which is inexpensive, operates stably, has high performance and is excellent in productivity.

Another object of the present invention is to provide a stable optical switch which has no mechanically movable part and is excellent in durability.

Another object of the present invention is to provide an optical switch having a structure that enables high density switching easily.

[0022]

The above object can be achieved by an optical path changing method and an optical switch according to the present invention. In summary, the first aspect of the present invention is an optical path conversion method for changing the optical path of light incident on an optical switch point, in which a fluid medium and a refractive index different from that of the fluid medium are provided between electrodes arranged to face each other. A switching material that is movable by an electric field is present, and the switching material is moved by changing the electric field between the electrodes to change the optical path of the light incident on the optical switch point. This is the optical path changing method.

According to one embodiment of the present invention, when a voltage is applied between the electrodes, an unequal concentrated electric field is formed between the electrodes. According to another embodiment, the electrodes arranged to face each other have different electrode shapes so that an unequal concentrated electric field is generated in one of the electrodes.

According to the second aspect of the present invention, in the optical switch having at least one optical switch point for changing the optical path, and the optical switch element is provided at the optical switch point, the optical switch elements face each other. An electrode arranged and a fluid medium formed between the electrodes,
A cell having a refractive index different from that of the fluid medium and containing a switching material that is movable by an electric field;
There is provided an optical switch, wherein the switching material is moved by changing an electric field generated between the electrodes to change an optical path of light incident on the optical switch point.

According to an embodiment of the second aspect of the present invention, the fluid medium is a gas or a liquid, and the gas is air.
It is nitrogen gas or carbon dioxide gas, and the liquid can be an electrically insulating liquid. The electrically insulating liquid may be silicone oil, a petroleum hydrocarbon compound, a liquid having a polar group, or a mixture of two or more of these liquids. At this time, preferably, the electrically insulating liquid has a viscosity of 200 cs (centistokes) or less.

According to another embodiment of the second aspect of the present invention, the switching material is an object electrically charged in the fluid medium. If desired, the switching material is composed of at least two objects of different charging series. Further, the switching material is formed of a film- or particle-shaped polymer compound or a conductive material, the polymer compound is polyethylene or polystyrene, and the conductive material is a metal or a conductive organic substance.

According to another embodiment of the second aspect of the present invention, the switching material has a dielectric constant different from that of the fluid medium.

According to another embodiment of the second aspect of the present invention, the optical path is an optical fiber and / or an optical waveguide segment. Preferably, a micro condenser lens, or a micro condenser lens and a collimator are provided at the tip of the optical fiber.

According to another embodiment of the second aspect of the present invention, the electrodes arranged so as to face each other have different electrode shapes.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The optical path changing method and optical switch according to the present invention will be described below in more detail with reference to the drawings.

Example 1 FIGS. 1 and 2 show one row optical path 11 and this row optical path 11.
Having two column optical paths 21 and 22 orthogonal to each other,
1 shows a 1 × 2 matrix optical switch 1. In this optical switch, at two intersections of the row optical path 11 and the column optical paths 21 and 22, that is, at the optical switch points 3 (3a and 3b), there are intersection switch elements (that is, optical switch elements) 2 (2a, 2a).
b) is placed. Optical switch element 2 (2a, 2b)
Has a function of changing the optical path of the light traveling through the row optical path 11.

In the configuration example shown in FIG. 1, the optical switching element 2
When a is off, the light traveling along the optical path 11 passes through the optical switch point 3a as it is, is reflected by the optical switch element 2b arranged at the optical switch point 3b being turned on, and the optical path is formed in the column optical path 22. Change can be switched.

In the configuration example shown in FIG. 2, the optical switching element 2
Both a and 2b are turned off, and the light traveling through the optical path 11 passes straight through the optical switch elements 2a and 2b and travels straight.

FIG. 3 shows a plurality (N) of row optical paths 11, 12,
18 and a plurality (M) of column optical paths 21, 22 ,.
.... N × M matrix optical switch 1 consisting of 28
In this example, an 8 × 8 matrix optical switch 1 is shown. In this configuration example, the optical switch element 2 of the row optical paths 13 and 14
Only the light beams a and 2b are turned on, and the lights traveling through the row optical paths 13 and 14 are reflected by the optical switch elements 2a and 2b, and the optical paths are switched to the column optical paths 26 and 24, respectively. , 24. The other optical switching elements are turned off, and the light passes through the optical switching elements as they are and goes straight on the row optical path.

FIG. 4 shows an embodiment of the optical switch of the present invention. In the present embodiment, the case where the present invention is applied to the 1 × 2 matrix optical switch 1 shown in FIG. 1 will be described, but the present invention is not limited to this, and FIG.
It is also applicable to the N × M matrix optical switch 1 as described above.

In this embodiment, the optical switch 1 has an electrically insulating substrate 5 which is a spacer. Any material may be used as the substrate 5, but the thickness is, for example, 0.3.
Polystyrene, epoxy, polymethylmethacrylate (PMMA), silicon dioxide and the like, which are light-transmissive resins having a thickness of up to 2.0 mm, are preferably used. In this embodiment,
A light-transmitting polystyrene having a thickness of 1.0 mm was used.

As shown in FIGS. 4 to 6, in the substrate 5,
In this embodiment, two cells (cavities) 7 (7a, 7b) are formed aligned in the optical axis direction of the row optical path 11. In the present embodiment, each of the cavities 7a and 7b is a quadrangular prism-shaped through hole having a rectangular cross section formed by penetrating from the upper surface to the lower surface of the substrate 5. Further, in order to install the optical fibers g11i and g11o forming the row optical path 11, the V-shaped groove 6 is formed in the substrate 5 so as to be aligned in the optical axis direction of the row optical path 11 and communicate with the cell. . Similarly, the substrate 5 has the optical path 1
The V-shaped groove 6 for installing the optical fibers g21o and g22o forming the column optical paths 21 and 22 is formed in a mode orthogonal to the optical axis direction of 1, and the optical fibers are arranged.

An electrode 411 (upper surface) is sandwiched between the upper and lower surfaces of the substrate processed as described above so as to sandwich the cell 7, and
The electrodes 421 and 422 (bottom surface) are arranged to face each other.
The electrode 411 is sized and shaped so as to cover both upper surfaces of the cells 7a and 7b, and the electrodes 421 and 422 are respectively formed into the cells 7a and 7b.
The size and shape cover b.

The cell 7 (7
A fluid medium and a switching material 8 (8a, 8b) having a refractive index different from that of the fluid medium and movable by an electric field are accommodated inside the a, 7b). According to the present invention, the electrodes 411 and 421,
By changing the electric field between the electrodes 411 and 422, the switching material 8 (8a, 8b) is moved to change the optical path of the light incident on the optical switch points 3a, 3b.

The fluid medium contained in the cell 7 (7a, 7b) is a gas or a liquid, and is air (preferably atmospheric pressure) according to this embodiment. As the gas other than air, for example, a gas such as N ₂ (nitrogen) gas or CO ₂ (carbon dioxide) gas may be used. The pressure of this gas is preferably about atmospheric pressure in terms of mechanical structure, but is not necessarily limited to this atmospheric pressure and is equal to or higher than the atmospheric pressure estimated by Paschen's law to the extent that electric discharge does not occur inside the cell 7. Atmospheric pressure is enough.

According to this embodiment, the switching material 8 (8
As can be understood by also referring to FIGS. 5 and 6, a, 8b) are film pieces formed in an isosceles triangle shape whose base is the diagonal line of the cell 7 (7a, 7b). The film piece is made of a material having light reflectivity.

Further, the switching material 8 (8a, 8b)
Is the cell 7 (7a, 7b) as shown in FIGS.
Inside, mechanically unrestrained state, that is, cell 7 (7a, 7
Substrate 5 and electrodes 411, 421, 42 constituting b)
It is stored in a state where it is not mechanically connected to any part of 2. That is, there is no mechanically connected support member that supports the switching material 8.

To further explain, used in this embodiment,
Switching material 8 (8a, 8) movable by an electric field
As b), a conductive material such as a metal or a conductive organic substance, a substance which is electrically charged in the cell 7 (in this case, the cell), or a substance having a high dielectric constant, for example, A substance having a relative dielectric constant of 10 or more is preferable. The term "conductivity" as used herein means the degree to which it can be regarded as substantially conductive within the application time of the voltage applied between the electrodes facing each other during switching. In this example, a metal or alloy foil having a volume resistivity of 10 ¹¹ Ωcm or less, preferably 10 ⁶ Ωcm or less was used. The thickness of the foil is not limited, but is, for example, 2 μm to 200 μm.

In this embodiment, the switching material 8 (8a,
As described above, the shape of 8b) is preferably a conductive isosceles triangle arranged on the diagonal line of the bottom surface of the cell 7 so as to easily serve as a mirror. Further, if it can serve as a mirror, it may be in the form of some fragments. For example,
When the conductive isosceles triangle-shaped switching materials 8a and 8b are used, the base of the isosceles triangle (the side facing the apex sandwiched by the isosceles) is arranged on the diagonal line of the bottom surface in the cell 7. To do. By applying a voltage to both electrodes, electrostatic charges gather at the vertices of the isosceles triangle as shown in FIG. Therefore, the apex of the isosceles triangle of the switching material 8 is pulled in the electrode direction by electrostatic force so that the switching material 8 straddles between both electrodes by the electric field of the conductive isosceles triangle shape, and serves as a mirror. be able to.

Optical fibers g11i, g11o, g21
o and g22o are accurately installed at desired positions on the electrically insulating substrate 5 using the V groove 6. Therefore, the light that has passed through the inside of the optical fiber g11i is not shown in FIG.
It passes through the two cells 7 (7a, 7b) and is guided to the inside of the optical fiber g11o arranged facing each other. The area 7c (FIG. 6) between the two cells 7 (7a, 7b) is made of at least a transparent material to allow the transmission of light, or alternatively the two cells 7 (7a, 7b). It is also possible to form a through hole at least at a position corresponding to a light passage portion between the two to connect the two cells 7 (7a, 7b).

At the tip of the optical fiber g11i, that is, the cell 7 of the optical fiber g11i shown in FIGS.
The tip of the optical fiber g11i close to
It is possible to provide a micro condenser lens ML as shown in FIG. For example, the micro condenser lens ML is attached to one end of a holder 9 which also serves as an optical fiber sleeve and a lens holder, and the other end of the holder 9 is inserted into the optical fiber to be attached to the optical fiber. Further, a collimator (not shown) can be attached.

According to this structure, the optical fiber g11i
The light emitted from the light source is diffused to be a parallel light beam without spreading, or is converged and is incident on the opposing optical fiber. As the micro-condensing lens ML, for example, SELFOC Micro-lens (trademark) for optical fiber manufactured by Nippon Sheet Glass Co., Ltd. may be used.

A voltage is applied between the electrode 411 and the electrodes 421, 422 at an electric field strength such that no discharge occurs in the cell 7, for example, about 25 kv / cm or less. As shown in FIGS. 4, 5 and 6, the switching material 8 (8a, 8b) in the cell 7 moves so as to be pulled between the opposite electrodes by electrostatic force, that is, in FIG. From the solid line position where no voltage is applied to the position where the voltage is applied to the alternate long and short dash line position, a reflective surface is formed on the diagonal line of the bottom surface in the cell 7. Therefore, the light emitted from the optical fiber g11i and parallel to the optical fiber g11i collides with the switching material 8b having a reflection surface, does not enter the optical fiber g11o, and changes its optical path to enter the optical fiber g22o.

When a voltage is applied between the electrode 411 and the electrode 421, the light emitted from the optical fiber g11i enters the optical fiber g21o. If no voltage is applied between the electrode 411 and the electrodes 421 and 422, the light emitted from the optical fiber g11i will be emitted from the two cells 7 (7a, 7a
Go straight through b) and go through the optical fiber g11o
Incident on.

That is, by changing and switching the voltage applied between the electrode 411 and the electrodes 421 and 422,
Switch the optical path of the light emitted from the optical fiber g11i,
It is possible to feed them into desired optical fibers g11o, g21o, g22o.

Example 2 FIG. 8 shows another embodiment of the optical switch 1 of the present invention.

Cell 7 (7a, 7b) of the embodiment shown in FIG.
6, the cell 7 (7a, 7b) formed in the substrate 5 is a through hole having a rectangular cross section formed by penetrating from the upper surface to the lower surface of the substrate 5. However, in this embodiment, as can be better understood by also referring to FIG. 9, the cell 7 (7a, 7b) of the triangular prism having the rectangular cross section shown in FIG. It is formed.

In this embodiment, the substrate 5 is made of transparent material.

An electrode 411 (upper surface) is sandwiched between the cell 7 and the upper and lower surfaces of the substrate processed as described above,
The electrodes 421 and 422 (bottom surface) are arranged to face each other.
The electrodes 421 and 422 arranged on the bottom surface of the cell 7 (7a,
7b) has the same shape as the triangle.

The cell 7 (7
Switching materials 8a and 8b movable by an electric field are housed inside a and 7b).

As described above, the switching material 8 (8a, 8b) is mechanically unconstrained in the cell 7 (7a, 7b), that is, the substrate 5 constituting the cell 7 (7a, 7b).
Also, it is stored in a state where it is not mechanically connected to any part of the electrode. In this embodiment, the switching material 8
(8a, 8b) are fine charged particles that reflect light. Therefore, when a voltage is applied between the opposing electrodes that sandwich the triangular prism-shaped cell 7 (7a, 7b), it is movable by the electric field,
The charged particles 8 (8a, 8b) have their cells 7 (7a, 7b)
Flying to b), the portion of the surface 10 including the oblique side of the triangle of the cell 7 (7a, 7b) is used as the light reflecting surface. This allows
The surface 10 can effectively reflect light.

Charged particles 8a, 8 which are switching materials 8
b can be a powdery substance having a diameter smaller than the diameter of the beam of light emitted from the optical fiber g11i (9 μm), for example, negatively charged polyethylene particles having a volume average particle diameter of 2 to 4 μm, It is also possible to use a powdery body composed of negatively charged polystyrene particles.

In this case, in the cell 7 (7a, 7b) and the charged particle 8 (8a, 8b) therein, the light emitted from the optical fiber g11i is directed to the particle 8 (8a, 8b) which is moved by being pulled by the electric field. It must be configured to reflect light when it collides. In order to form the charged particles 8 (8a, 8b) in a spherical shape with an organic material, for example, a known liquid suspension polymerization method, air spray method, or the like can be adopted.

When the particles 8 (8a, 8b), which are the switching material movable by the electric field, are conductive particles and are metal particles, when the electric field is applied between the electrodes, the particles 8 (8
a, 8b) emits a charge having a polarity opposite to that of the electrode to an electrode adjacent to a, 8b), and the particles 8 (8a, 8b) are charged with a charge having the same polarity as the electrode and fly toward the counter electrode. To do.
When electric charge is injected into the particles 8 (8a, 8b) from the electrodes, the particles 8 (8a, 8b) are charged to the same polarity as the electrodes and fly to the counter electrode side. In particular, if the surface of the opposing electrode is a bare electrode, the particles 8 (8a, 8b)
Flies between the electrodes and reciprocates. Triangular prismatic cell 7 (7
a, 7b) have many flying particles 8 (8a, 8b)
Cells 7 (7a, 7a) filled with
The flying particle surface formed along the surface 10 corresponding to the hypotenuse of the triangle in b) serves as a mirror.

The diameter of the light (9 μm) emitted from the optical fiber g11i is set in one cell 7 (7a, 7b).
m) or more, for example, the volume average particle size is 10μ
m to 30 μm or 60 μm, that is, 1 of the diameter of light
~ 3 times, or 6 times the volume average particle size of the charged particles 8 (8
It has been found that the optical switching 8 is effective even if one each of a) and 8b) is charged.

Example 3 FIG. 10 shows another embodiment of the optical switch 1 of the present invention.

Cell 7 (7a, 7b) of the embodiment shown in FIG.
In the above, the cell 7 is formed on the top surface and the bottom surface of the light transmissive substrate 5.
Electrodes 411 (upper surface) sandwiching (7a, 7b)
And the electrodes 421 and 422 (bottom surface) are arranged so as to face each other, but in this embodiment, the cell 7 (7) of the embodiment shown in FIG.
In order to make the shape of the electric field formed by the electrodes sandwiching a and 7b) into a desired shape, the shape of the electrodes sandwiching this cell is set to a desired shape.

That is, in this embodiment, the cell 7 shown in FIG.
Electrode 411 and electrodes 421, 42 sandwiching (7a, 7b)
Instead of 2, as shown in FIG.
2 and the electrodes 423 and 424 so as to form a triangle. That is, the electrode 412 is composed of triangular electrodes 412a, 412b having substantially the same shape as the cell 7 (7a, 7b), and the lower surface of the cell 7 (7a, 7b) has a triangular shape substantially the same as the cell shape. Electrodes 423 and 424 are arranged.

The electric field shape in the cell 7 (7a, 7b) formed by these electrodes 412, 423, 424 is formed into a desired electric field shape corresponding to the opposing triangular electrode shape. To this end, the cells 7 (7a, 7b) of FIGS. 8 and 9
As shown in, the light reflecting surface 10 is formed without partitioning the cells 7 (7a, 7b) on a diagonal line.

Therefore, also in this embodiment, the surface 10 including the oblique side of the triangle of the cell 7 (7a, 7b) is caused by the particles 8 (8a, 8b) which are the switching material flying between the electrodes.
The portion of can be a light reflecting surface. This is cell 7
This is because the flying range of the particles 8 (8a, 8b) in (7a, 7b) is determined by the shapes of the electrode 412 and the electrodes 423, 424.

In other words, the electrodes 412 facing each other,
The flight range of the particles 8 (8a, 8b) can be determined by the electric field distribution shape pattern formed by the electrodes 423, 424. That is, by changing the electrode shape, the light reflecting surface can be easily changed mathematically and physically, and a desired light reflecting surface can be designed and formed. The particles 8 (8a, 8b) that are the switching material in this case may be charged particles or conductive particles. Without expecting light reflection,
For absorption, particles 8 (8a, 8b) may be particles made of a material that does not reflect light but absorbs light. If it absorbs visible light, black particles may be used.

Example 4 According to the previous example, the fluid medium contained in the cell 7 (7a, 7b) was described as a gas such as air, but according to another example of the present invention. For example, as a fluid medium,
It is also possible to use liquids. An electrically insulating liquid is preferably used as the liquid.

According to this embodiment, the switching material 8 is
By forming particles in an electrically insulating liquid that are in a charged state and causing the particles to migrate and fly by an electric field, the light reflection effect can be obtained as in the previous embodiment.

The electrically insulating liquid as the fluid medium is, for example, Isopar which is a petroleum hydrocarbon compound, and
Liquid such as silicone oil is good. In order to easily and rapidly move the particles 8 (8a, 8b), which are switching materials, by the electric field, the viscosity is preferably low. In this case, the particles 8 (8a, 8b) that are the switching material are preferably particles made of a polymer compound (synthetic resin) such as polyethylene. These particles are often negatively charged in the electrically insulating liquid.

FIG. 11 shows particles 8 (8a, 8b) housed in the cell 7 (7a, 7b) and having different charged series on at least the particle surface. In this embodiment, it is preferable that at least two kinds of particles 8a and 8b as the switching material 8 are used and the sizes of the particles 8a and 8b are different.

Further, the electrically insulating liquid as the liquid medium is isopar or silicone oil having a viscosity of 200 cs (centistokes) or less, preferably 100 cs to 80 cs or less, usually 10 cs or more, and is used in the liquid medium. , The two types of switching materials 8 (8a, 8b) shown in FIG. 11 are mixed.

The switching material 8 (8a, 8b) is composed of black magnetic particles 8a containing Fe having a particle size of 30 to 200 .mu.m as a main component and absorbing light having a particle size of 10 to 60 .mu.m. And particles 8b whose main component is a hydrocarbon resin. When these two types of switching materials 8 (8a, 8b) are mixed, the particles 8b mainly composed of a hydrocarbon resin such as polyethylene that reflects light are negatively charged and mainly black Fe that absorbs light is absorbed. The magnetic particles 8a as a component are positively charged and maintain a suspended state in the isopar liquid which is an electrically insulating liquid.

Here, when a voltage is applied between two electrodes facing each other with the cell 7 (7a, 7b) sandwiched therebetween, and an electric field is applied, one of the negatively charged switching materials 8 is applied to the positive electrode side. Particles 8b mainly composed of a reflective type hydrocarbon resin such as polyethylene are gathered, and positively charged black Fe which is another kind of the switching material 8 and which absorbs light is collected on the negative electrode side. The magnetic particles 8a as the main component are collected.

Therefore, the light is absorbed near the negative electrode and the light is reflected near the positive electrode.

According to this embodiment, the optical fiber g11i
When the optical fiber g11i is arranged so that the light emitted from the electrode is near the electrode 412 side, in the cell 7a in which the electrode 412 is a negative electrode, the positively charged light is absorbed near the electrode 412 side with respect to the electrodes 423 and 424. Magnetic particles 11a containing black Fe as a main component are gathered, light is absorbed by these particles 11a, and an optical fiber g21 on the side receiving the light is received.
Light does not reach o and g22o.

On the contrary, in the cell 7b having the electrode 412 as a positive electrode with respect to the electrode 424 and sandwiched by both electrodes, a hydrocarbon resin such as polyethylene, which is negatively charged and reflects light, is mainly formed near the electrode 412 side. The particles 8b as a component are gathered, light is reflected by these particles, the light is advanced to the optical fiber g22o on the light receiving side, and the optical path can be changed and switched.

Embodiment 5 FIG. 12 shows another embodiment of the optical switch of the present invention. This embodiment is a modification of the embodiment shown in FIG.
It is also a modified example of.

In this embodiment, an optical waveguide is used as the optical path. Optical fibers g11i, g11o, g21o, g2
2o is a single mode optical fiber, and a single mode fiber having a core diameter of about 9 μm was used. Optical waveguides pg11i, pg11o, pg21o, p
The g22o is provided on the electrically insulating substrate 5 that also functions as a spacer.

Optical waveguides pg11i, pg11o, pg2
1o and pg22o may be directly provided on the substrate 5, or optical waveguides pg11i, pg11o, pg21o, and pg formed on a polyimide resin flexible sheet.
22o may be provided by being laminated on the substrate 5 and then being bonded. As an example of the substrate in the former case, a Si substrate or LN (L
iNbO3) substrate. On this substrate, as a waveguide film, a CVD (C
The film may be formed by a chemical vapor deposition method, and the optical waveguide may be formed by a known method using, for example, a photolithography technique. Or in MIT in 1995
An optical waveguide using a photonic crystal, which was theoretically predicted by Joannopoulos and others, may be formed on the substrate 5.

In this embodiment, the optical fibers g11i and g1
1o, g21o and g22o are accurately fixed to the V groove 6 provided on the substrate 5 as in FIGS. 4, 8 and 10, and the center (optical axis) of the core of the single mode optical fiber is exactly Optical waveguides pg11i, pg11o, p
They are arranged so as to coincide with the optical axes of g21o and pg22o. The alignment accuracy of the optical axis requires submicron accuracy.

Further, the optical fibers g11i, g11o,
g21o and g22o and optical waveguides pg11i and pg11
For connection with o, pg21o, and pg22o, either a generally known adhesive connection method or a fusion splicing method may be adopted. However, in the present embodiment, an ultraviolet curable adhesive connection method is used. Using.

Further, the light entrances of the optical waveguides pg11i, pg11o, pg21o, pg22o into which light enters the optical waveguide side are designed to be slightly wider. For example, a connection port (light entrance) of the optical waveguide pg11i with the optical fiber g11i, a light entrance for receiving light that has passed through the cell 7b of the optical waveguide pg11o, and a light reflected by the optical switch element 2 of the optical waveguide pg21o. The light entrance and the light entrance that receives the light reflected by the optical switch element 2 of the optical waveguide pg22o are designed in a trumpet shape so as to be slightly wider, and the light loss at the connection portion is reduced as much as possible.

Further, the optical waveguides pg11o, pg21o,
optical fiber g11o and g2 from pg22o, respectively
When connecting to 1o and g22o, they may be directly connected to the optical fibers g11o, g21o, and g22o.

However, when connecting to a multi-mode optical fiber, there is no problem so much, but when connecting to a single-mode optical fiber having a core diameter of about 10 μm, the core diameter is widened at the entrance, and the single diameter gradually increases. A short optical fiber for connection matched with the core diameter of the mode is used as an optical waveguide pg11o, pg21o, pg22o.
And single mode optical fibers g11o, g21o,
g22o and optical waveguides pg11o, p
It is desirable to connect g21o, pg22o and the single mode optical fibers g11o, g21o, g22o.

The cell 7 (7a, 7b) is a hollow of a triangular prism as in the case of the embodiment of FIG.
The light can be switched by the optical switching element 2 at the optical switching point 3 by the electric field created by the opposing electrode pair composed of 2 (412a, 412b) and the electrodes 423, 424.

The fluid medium in the cells 7 (7a, 7b) is gas (air), and the switching material 8 (8a, 8b) movable by the electric field inside the cells is the conductive material shown in the embodiment of FIG. Triangle-shaped (isosceles triangle) filler (membrane piece) having a particle size of about 50 μm to 20 shown in the embodiment of FIG.
Good results were obtained by using 0 μm conductive particles and further polystyrene particles having a negatively charged and chargeable particle size of 30 μm to 80 μm.

The shape of the cells 7 (7a, 7b) is not limited to the triangular prism shape and may be a cylinder. In this case, the switching material 8 (8a, 8b) is the optical waveguide pg11.
From a practical point of view, it is almost satisfactory if the particle size has a light-reflecting surface having a cross-sectional area that is substantially several times larger than the cross-sectional area of light passing through o, pg21o, and pg22o.

Embodiment 6 FIGS. 13 and 14 show another embodiment of the optical switch of the present invention. The optical switch of the present embodiment changes the electric field to form an unequal concentrated electric field in the cell 7 to form an electrically insulating property as a liquid medium having a higher dielectric constant than a bubble as the switching material 8 in a place where the electric field is strong. By drawing in and moving the liquid, the bubbles provided in the electrically insulating liquid are chased and the optical path is changed.

FIG. 13 is an explanatory diagram showing the operation.
In FIG. 13, optical fibers g11i, g11o, g2
1o and g22o are set in the V groove 6 in the same manner as shown in FIG. Further, a micro condenser lens ML similar to that shown in FIG. 7 is provided at the tip of the optical fiber.
13 and 14, the cell 7 (7a, 7b) is
Similar to the embodiment shown in FIGS. 8 and 9, it is a hollow of a triangular prism.

Electrodes 412p, 412 are provided on the top and bottom surfaces of the cell 7 (7a, 7b) through an electric insulator layer 12 made of the same material as or a different material from the light transmissive substrate 5.
r, 423, 424 are arranged. The electrode 412p is a light transmitting electrode, and the electrode 412r is a light reflecting electrode.

The electrodes 423 and 424 are used for the cell 7 (7a, 7a).
It has a triangular shape having substantially the same shape as b). On the other hand, the electrode 412
Although p and 412r are separated from each other, the electrode 41 arranged corresponding to the electrodes 423 and 424 so as to form a triangular shape having substantially the same shape as the cell 7 (7a, 7b).
2pa, 412ra; electrodes 412pb, 412rb.

The fluid medium in the cells 7 (7a, 7b) is a viscous liquid having a higher relative permittivity and a lower electric insulation than the bubbles which are the switching material 8. In this embodiment, the viscosity is 0.5c.
Silicone oil having a low viscosity of about s to 100 cs was used. For example, the relative permittivity εr of silicon oil is 10
It is about 2.65 in cs and about 2.72 in 100 cs.

Electrode 412 facing electrodes 423 and 424
This bubble 8 is generated by the electric field applied between p and 412r.
In order to move (8a, 8b) in the direction in which the electric field is smaller, the electrically insulating liquid having a higher relative dielectric constant than the bubble 8 (8a, 8b) is drawn in to move the bubble 8 (8a, 8b) to a place with a lower electric field. The optical switch can be achieved by pursuing.

Therefore, in this embodiment, the bubbles 8 (8a, 8a
As b), air bubbles of 1.00029 were used under the conditions that the relative permittivity was close to 1, the absolute refractive index was 1 atm, and the temperature was 0 degree Celsius.

14A and 14B show the arrow X in FIG.
Cell 7 (7a, 7b) of the optical switching element viewed from
It is a sectional view of a part, and the operation principle is shown and explained.

FIG. 14A shows an example in which a voltage is applied between the electrode 423 and the light transmitting electrode 412 pa by the power source V, and FIG. 14B shows the electrode 424 and the light reflecting electrode 4.
An example is shown in which a voltage is applied by the power supply V to 12 rb.

FIG. 14A shows that the electric field in the cell 7a surrounded by the electrode 423 and the light transmitting electrode 412pa is the electric field in the cell 7a surrounded by the electrode 423 and the light reflecting electrode 412ra. Since it is stronger, the electrically insulating liquid having a relative dielectric constant higher than that of the bubble 8a is drawn into the area inside the cell 7a surrounded by the electrode 423 and the light transmission electrode 412pa, and as a result, the relative dielectric constant is increased. The air bubbles 8a having a low height are driven in the direction of arrow A in the cell 7a surrounded by the electrode 423 and the light reflecting electrode 412ra.

Therefore, as shown in FIG. 13, the light passing through the optical fiber g11i proceeds straight without being blocked by the bubble 8a in its optical path.

In FIG. 14B, the electric field in the cell 7b surrounded by the electrode 424 and the light reflection electrode 412rb is
Since the electric field in the cell 7b surrounded by the electrode 424 and the light transmission electrode 412pb is stronger than the electric field in the cell 7b, the electrically insulating liquid having a higher relative permittivity than the relative permittivity of the bubble 8b is changed to the electrode 424.
The bubble 8b having a low relative dielectric constant is drawn into the region inside the cell 7b surrounded by the light transmitting electrode 412rb.
It is driven in the direction of arrow B in the cell 7b surrounded by the electrode 424 and the light reflection electrode 412pb. At this time, the bubble 8b is set so as to contact the wall of the substrate 5 which is the wall of the cell 7b.

Electrodes 423 and electrodes 412ra, 412pa
The electric field strength applied between the electrode 424 and the electrode 4
The electric field strength applied between 12 rb and 412 pb is 5
Sufficient switching operation function could be confirmed by selecting an electric field of 0 V / 20 μm or less and 16 V / 20 μm or more and a zero electric field.

Therefore, as shown in FIG. 13, the light that has passed through the optical fiber g11i undergoes total reflection at the boundary surface between the substrate 5 and the bubble 8b, enters the optical fiber g11o, and is reflected without proceeding to the direction of the optical fiber g22o. Is guided by.

Although the electrically insulating silicone oil is used as the fluid medium in the present embodiment, it is not limited to this, but isoper, which is a petroleum hydrocarbon compound, has a polar electrically insulating liquid such as silicon. Among the hydrogen elements of oils and hydrocarbon compounds, a polar electrically insulating liquid having a polar group in which one or more hydrogen elements at local positions are replaced with halogen atoms of F, Cl, Br, and I You may use. Alternatively, it is also effective to use a mixed liquid of silicone oil or a petroleum hydrocarbon compound and a liquid having a polar group.

In the present embodiment, the volume and shape of the cell 7b surrounded by the electrode 424 and the light transmitting electrode 412pb and the volume and shape of the cell 7b surrounded by the electrode 424 and the reflecting electrode 412rb. The volume and the shape are designed to be different, and in the present embodiment, the latter volume is smaller than the former volume.

On the other hand, conversely, the volume inside the cell 7b surrounded by the electrode 424 and the light transmitting electrode 412pb is the volume inside the cell 7b surrounded by the electrode 424 and the reflecting electrode 412rb. In the case of a smaller design, when it is desired to reflect light, the bubbles 8b are sufficiently in contact with the wall of the substrate 5 which is the wall of the cell 7b, and the close-up area is widened, so that the cell 7b which is the total reflection surface is formed. There is an advantage that the boundary surface between the wall of the substrate 5 which is the wall of the cell and the bubble 8b is stable.

Furthermore, by making the volume inside the cell 7 (7a, 7b) formed by the opposing electrodes different, for example, in FIG. 14A, the light reflection electrode 412pa
The voltage is not applied between the electrode 423 and the electrode 423, and the electric field between the electrodes is weakened to generate a restoring force that causes the distorted bubble 8a to have an original spherical shape. The bubble 8a can be brought close to the light reflection position, that is, the region inside the cell 7a surrounded by the electrode 424 and the light transmission electrode 412pa, which is preferable.

Example 7 FIG. 15 shows an example in which the optical switch (1 × 2 matrix switch) shown in Example 6 is expanded to a 2 × 2 matrix optical switch. To 32x32,
Furthermore, it has been found that the same effect can be obtained by expanding to N × M.

In the embodiment shown in FIG. 15, FIG. 13 and FIG.
Members having the same configurations and functions as those of the optical switch of the sixth embodiment shown in FIG. However, a part of the expression method changes with the expansion, and for example, as the number of cells 7 increases, the individual cells 7
The expression of the symbol was changed. Further, as the number of cells has increased, a symbol indicating the increased number of electrodes has been newly added as an electrode.

In FIG. 15, cells 7 (7a1, 7b) are
1, 7a2, 7b2) are triangular prism cavities as in the embodiment shown in FIG.

Cell 7 (7a1, 7b1, 7a2, 7b)
The electrical insulator layer 12 made of the same material as the substrate 5 or a different material is provided on the upper surface and the bottom surface of 2) as in the sixth embodiment.
Through electrodes 412p, 412r, 413p, 413
r, 423, 424 are arranged. Electrode 412p,
Reference numeral 413p is a light transmitting electrode, and electrodes 412r and 413r are light reflecting electrodes.

The electrodes 423 and 424 are connected to the cell 7 (7a1,
7a2, 7b1, 7b2) and has a substantially triangular shape. On the other hand, electrodes 412p, 412r, electrodes 413p, 4
Although the electrodes 13r are separated from each other, the electrodes 412pa, 412ra are arranged corresponding to the electrodes 423, 424 so as to form a triangular shape having substantially the same shape as the cell 7 (7a1, 7a2, 7b1, 7b2); Electrodes 413pa, 4
13ra; electrodes 412pb, 412rb; electrodes 413p
b, 413 rb.

Cell 7 (7a1, 7b1, 7a2, 7b)
Since the fluid medium in 2) uses an electrically insulating liquid having a relative dielectric constant higher than the relative dielectric constant (about 1) of bubbles that are the switching material 8, instead of some hydrogen atoms forming molecules. Silicone oil having a polar group and having a viscosity of 30 cs (centistokes) substituted with F atoms and Cl atoms was used. If the viscosity is about 100 cs to 200 cs or less, a response speed that can withstand the demand without reducing the switching speed was obtained. If the viscosity is too low, the volatility becomes high, which is not preferable from the viewpoint of safety different from the performance. From this viewpoint, 10 cs or more is preferable.

Electrode 412 facing electrodes 423 and 424
cells 7 (7a1, 7b1, 7a2, 7b) due to the electric field applied between p, 412r, 413p, and 413r.
2) In order to move the bubbles 8 in the direction toward the weaker electric field, it is possible to achieve an optical switch by drawing in an electrically insulating liquid having a higher relative dielectric constant than the bubbles 8 and driving the bubbles 8 to a place with a lower electric field. It was That is, the light passing through the optical fiber g11i passes through the respective cells 7 (7a1, 7b1) and reaches the optical fiber g11o to be passed,
Alternatively, the light can be reflected by the bubbles in any one of the cells 7 (7a1, 7b1) to reach either one or both of the optical fibers g21o and g22o as desired and allow the optical fibers to pass therethrough. did it.

Similarly, with respect to the light that has passed through the optical fiber g12i, this light is also transmitted to each cell 7 (7a).
2, 7b2) to reach and pass the optical fiber g12o, or the cell 7 (7a2, 7b2)
It was possible to cause the light to be reflected by the bubbles in any one of the cells to reach either one or both of the optical fibers g21o and g22o as desired, and allow the optical fibers to pass therethrough. That is, a 2 × 2 optical matrix
In the switch, the optical path could be freely changed as desired, and the performance and effects of the optical matrix switch could be fully confirmed.

As the electrically insulating liquid used here, a silicone oil having a polar group and a viscosity of 30 cs (centistokes) substituted with Cl atoms in place of a part of hydrogen atoms of a methyl group forming a molecule is used. Instead of 30
In the silicone oil of cs, iodine (I) or bromine (B
r) was used in which halogen elements (iodine, bromine) corresponding to 4% to 3% or less (at least 10% or less) of the number of molecules of silicon oil were dissolved. Good results have been obtained. This is because the effect of equivalently increasing the dielectric constant was obtained by providing the silicone oil with a slight ionic conductivity. This is also because the liquid is drawn into a place where the ionic conductivity is strong and the bubble is driven to a place where the electric field is weak.

In this embodiment, the optical switch of the sixth embodiment is replaced by two.
The case where the optical switch is expanded to the × 2 or N × M matrix optical switch has been described, but it is natural that the optical switch of the other embodiments can be expanded to a 2 × 2 or N × M matrix optical switch.

[0116]

As described above, the optical path conversion method and the optical switch of the present invention have a fluid medium and a refractive index different from that of the fluid medium between the electrodes arranged to face each other, and the fluid medium can be moved by an electric field. Since the switching material is caused to exist, the switching material is moved by changing the electric field between the electrodes, and the optical path of the light incident on the optical switch point is changed. (1) With a simple structure , Can perform stable operation. (2) Switching can be achieved with very little energy and the optical path can be changed. (3) Inexpensive, stable operation, high performance, and excellent productivity. (4) It has no mechanically movable part and is excellent in durability. (5) The structure is such that high density switching can be easily performed. Such an effect can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the operation of a 1 × 2 matrix optical switch.

FIG. 2 is a diagram illustrating the operation of a 1 × 2 matrix optical switch.

FIG. 3 shows an optical path N having a plurality of rows of optical paths 11, 12, ..., 18 and a plurality of columns of optical paths 21, 22 ,.
It is an operation | movement explanatory drawing of a xM matrix optical switch.

FIG. 4 is a perspective view showing an embodiment of an optical switch according to the present invention.

FIG. 5 is a cross-sectional view illustrating the operation of the switching material of the optical switch according to the present invention.

6 is a perspective view showing a state in which both electrodes are removed by the optical switch of FIG.

FIG. 7 shows an example in which a micro condenser lens is provided at the tip of an optical fiber.

FIG. 8 is a perspective view showing another embodiment of the optical switch according to the present invention.

9 is a perspective view showing a state in which both electrodes are removed by the optical switch of FIG.

FIG. 10 is a perspective view showing another embodiment of the optical switch according to the present invention.

FIG. 11 is a diagram showing particles having different charge series, which is an example of a switching material put in a cell.

FIG. 12 is a perspective view showing another example of the optical switch according to the present invention, in which an optical waveguide is used as an optical path.

FIG. 13 is a perspective view showing another example of the optical switch according to the present invention, in which an electrically insulating liquid is used as a fluid medium in a cell and bubbles are used as a switching material.

FIG. 14 is an explanatory diagram showing the operating principle of the optical switch of FIG.

FIG. 15 is a perspective view showing an embodiment of an optical switch (2 × 2 matrix optical switch) according to the present invention.

[Explanation of symbols]

1 Optical Switch 2 (2a, 2b) Optical Switch Element 3 (3a, 3b) Optical Switch Point 5 Substrate 6 V Groove 7 (7a, 7b) Cell 8 (8a, 8b) Optical Switching Material 10 Reflection Surface 11 Optical Path 12 in Row Electrical insulating layers 411, 421, 422, 412, 423, 424 Electrodes 412p, 413p Light transmitting electrodes 412r, 413r Light reflecting electrodes

Claims (18)

[Claims] 1. An optical path conversion method for changing the optical path of light incident on an optical switch point, wherein a fluid medium and a refractive index different from those of the fluid medium are provided between electrodes arranged to face each other, and An optical path conversion method characterized in that a movable switching material is present and the switching material is moved by changing an electric field between the electrodes to change an optical path of light incident on the optical switch point. 2. The optical path changing method according to claim 1, wherein when a voltage is applied between the electrodes, an unequal concentrated electric field is formed between the electrodes. 3. The optical path changing method according to claim 2, wherein the electrodes arranged to face each other have different electrode shapes, and an unequal concentrated electric field is generated in one of the electrodes. 4. An optical switch comprising at least one optical switch point for changing an optical path, wherein the optical switch element is provided with an optical switch element, wherein the optical switch element includes electrodes arranged to face each other, and A cell formed between the electrodes and having a fluid medium and a switching material that has a refractive index different from that of the fluid medium and that is movable by an electric field is included. An optical switch characterized in that the switching material is moved to change the optical path of light incident on the optical switch point. 5. The optical switch according to claim 4, wherein the fluid medium is gas or liquid. 6. The gas is air, nitrogen gas, or
The optical switch according to claim 5, wherein the optical switch is carbon dioxide gas. 7. The optical switch according to claim 5, wherein the liquid is an electrically insulating liquid. 8. The electrically insulating liquid is silicon oil, a petroleum hydrocarbon compound, a liquid having a polar group, or a mixture of two or more of these liquids. Optical switch. 9. The optical switch according to claim 7, wherein the electrically insulating liquid has a viscosity of 200 cs or less and 10 cs or more. 10. The optical switch according to claim 4, wherein the switching material is an object that is electrically charged in the fluid medium. 11. The optical switch according to claim 10, wherein the switching material is composed of at least two objects of different charging series. 12. The optical switch according to claim 4, wherein the switching material is a film-like or particle-like polymer compound or a conductive material. 13. The optical switch according to claim 12, wherein the polymer compound is polyethylene or polystyrene. 14. The optical switch according to claim 10, wherein the conductive material is a metal or a conductive organic material. 15. The optical switch according to claim 4, wherein the switching material has a dielectric constant different from that of the fluid medium. 16. The optical path is an optical fiber and / or an optical waveguide segment.
15. The optical switch according to any one of items 15 to 15. 17. The micro condensing lens, or a micro condensing lens and a collimator are provided at the tip of the optical fiber.
Light switch. 18. The electrodes, which are arranged to face each other, have different electrode shapes from each other.
<17> The optical switch according to any one of <17>.